Forward osmosis process to increase the concentration of a dilute metal salt solution and related processes

Abstract

Provided are forward osmosis processes to increase the concentration of a dilute metal salt solution, e.g., a vanadium electrolyte solution. In embodiments, such a process comprises: (a) delivering a draw solution to a draw chamber of a forward osmosis module, the draw solution comprising water and sulfuric acid at a draw acid concentration, wherein the draw solution is free of vanadium cations; and (b) delivering a feed solution to a feed chamber of the forward osmosis module, the draw and feed chambers separated by a membrane, the feed solution comprising water, vanadium cations, and sulfuric acid at a feed acid concentration that is lower than the draw acid concentration, wherein water passes across the membrane from the feed solution to the draw solution, thereby providing a concentrated vanadium electrolyte solution as a feed chamber output and a diluted acid solution as a draw chamber output.

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